


hen in the foxhouse

by tajemnica



Category: Haikyuu!!
Genre: Anal Fingering, Anal Sex, Animal Ears, AtsuHina, F/M, Foursome - F/M/M/M, Fox Tails, FoxTsumu, Frottage, M/M, Miyahina Four, Multi, Sibling Incest, Twincest, Vaginal Fingering, Vaginal Sex, foxsamu, hot dogging, osanatsu
Language: English
Status: Completed
Published: 2021-02-20
Updated: 2021-02-20
Packaged: 2021-03-16 15:22:06
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,310
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29578131
Author URL: https://archiveofourown.org/users/tajemnica/pseuds/tajemnica
Summary: there’s something weird about shouyou’s boyfriend. and, funnily enough, it’s not even the whole “fox” thing.(hinata natsu's gonna figure out what’s going on with the miya twins, and how her brother’s involved.)
Relationships: Hinata Natsu/Hinata Shouyou, Hinata Natsu/Hinata Shouyou/Miya Atsumu/Miya Osamu, Miya Atsumu/Miya Osamu
Comments: 14
Kudos: 46
Collections: Miyacest Gift Exchange





	hen in the foxhouse

**Author's Note:**

  * For [murcielag0](https://archiveofourown.org/users/murcielag0/gifts).



> for the queen of miyahina four—i hope you enjoy!

there’s something weird about natsu’s brother’s boyfriend. and, funnily enough, it’s not even the whole “fox” thing. 

(she’s always known miya atsumu’s got some kind of whole _fox_ thing going on, and not in a _furry_ sort of way, either—there’s just something a little… _foxish_ about him and his brother, both. 

sometimes, it…kinda looks like they’ve got fox ears, sticking up out of their hair? 

but then other times, it doesn’t. and once or twice, natsu’s pretty sure she’s even seen a tail, swishing behind atsumu when she’s been to visit the apartment he and his twin share with her brother. 

hinata’s never said anything about it in particular, so natsu never has, either… especially because they mostly just look like two totally normal twenty-something dudes—if your two totally-normal-twenty-something-dudes just happen to be especially tall and broad-shouldered and smirky and hot.)

no, all the fox stuff is whatever… kinda cute, even. but there’s still something weird about shouyou’s boyfriend… and shouyou’s boyfriend’s _twin_ , and the way they all live together... and the way they try to pretend like miya osamu _doesn’t_ slink from “his” room into “their room” every night after they think she’s asleep? that’s definitely part of it. 

osamu’s usually already gotten up and made breakfast by the time she wakes up, so she never quite manages to catches him in the act of sneaking back out, but she can’t help herself from staying up late, pretending to be asleep and listening in. holding her breath and trying to keep her hands from sneaking between her legs when she hears those hushed sounds coming from their bedroom. 

in the light of day, shouyou and atsumu are completely shameless, even more lovey-dovey than usual, endlessly touching one another and sharing kisses even in the middle of conversations... but it’s osamu that holds natsu’s attention. she’s too clever to fall for her brother’s simple misdirection, so she looks for all the funny little ways osamu almost touches them, almost gets involved and then flinches away at the last second. 

it almost makes her a little sad to see, in a funny way… it’s clear he’s not used to being separated, being cut off from the physical contact the other two share; she knows that this is a courtesy they’ve decided to show guests, and they seem committed to maintaining it throughout her stay. she’ll just have to crack them.

-

when it’s just a basic cross-training and conditioning day, natsu goes with shouyou and atsumu to the gym, eager to work on her own strength and skill, but when they have specific things to do with their team, natsu often finds herself just with osamu. 

they get along well enough, generally speaking—he’s a little awkward when it’s just them, a little overly-cordial, in stark contrast to the lively smart-ass he tends to be around shouyou and atsumu. natsu firmly believes they should be allies against their brothers’ collective bullshit, but osamu seems to want to give her a wide berth.

nevertheless, they wind up spending a fair bit of time together; sometimes she even goes to the restaurant with him, helping out just for something to do.

natsu can feel how nervous she makes him. is it how much younger she is? she may still be in high school, but she’s not a kid. she can hold her own. is he worried about her finding out that he’s involved with shouyou? he doesn’t need to worry about that—she’s going to get her answers one way or another. 

“samu-san,” she starts presently. she catches a glimpse of his little ears flicking, the anxious twitch of his tail out of the corner of her eye, but they’re gone once she turns her head. “may i ask you a question?”

he grunts an assent, continuing with his tasks as though her question will be of no consequence. well, he’ll see. 

natsu cocks her head to the side, wide-eyed and innocent, almost pouting, as she asks: “are you fucking my brother, too?”

osamu freezes, clearing his throat. “‘scuse me?”

“i think you heard me,” natsu smiles, “and you’re just stalling. are you? does atsumu-san watch? or, wait—does atsumu-san even know?”

“of course he—” osamu cuts himself off, running a hand through his hair. “nacchan,” he tries again, “yer brother is an adult. what he does in the privacy of his bedroom is not your concern.”

natsu scrunches up her face, a parody of confusion. got him. “ _my_ brother? not _my_ concern?”

“no. not your concern.” he looks proud of his measured, reasonable, grown-up response.

“‘samu-san,” natsu says slowly, savoring the moment before he sees the trap, “you didn’t say _our brothers_ . or _our_ concern.”

he blinks at her. he still doesn’t see it, so she presses onward. “so, does that mean... what _your_ brother does in the privacy of his bedroom _is_ your concern?”

osamu’s eyebrows pinch. so much for the smarter twin. his ears are back, too, and they’re _back,_ pressed flat and panicky against his head, like a cornered animal. 

“hey,” she says gently, soothing. “it’s okay. you can trust me. i’m not gonna tell.”

-

that night, when osamu sneaks into the other bedroom, all she hears is quiet, murmuring conversation, and though she can’t discern any specifics, it’s easy enough to guess what it’s about. she drifts off to their soft low voices and just as she’s about to fall asleep, she catches herself feeling a weird kind of lonely, a little left out. 

the next day things are a little bit different. it’s subtle, but more than enough to spot if you’re looking—and natsu definitely is. osamu looks a little less uptight, a little more at home and comfortable, letting himself linger closer, brushing against shouyou and even sneaking a kiss when he thinks she’s not looking. he still steers clear of atsumu, although they do that strange telepathic twin thing, seemingly having entire conversations with just their eyes… and their fox ears. 

she’s seeing more of those, too… more softly swishing tails, more pointed ears pricked forward with attention. she hasn’t stopped seeing them out of the corner of her eye, but now, when she looks, they’re still there. undeniable. so she finally bites the bullet and asks shouyou about that, too.

“the fox thing?” he repeats doubtfully, with a little frown.

natsu rolls her eyes. “oh, come on, you don’t have to pretend you don’t see it! yes, the fox thing!”

shouyou worries his lips, like he’s weighing his options, and then seems to make a decision. “hey, tsumu?”

atsumu comes when called, bouncing on the balls of his feet. no fox stuff. “yeah?”

“tail, please?” 

atsumu blushes, looking down. “i don’t—” he starts, kicking at the floor, but he trails off as shouyou runs a comforting hand down his low back.

“nacchan said she sees ‘em sometimes already, so. i thought you may as well relax.”

atsumu’s blush deepens as shouyou’s hand meets soft fur. “just means they trust you,” shouyou explains, gently bringing the tail around atsumu’s hip. 

natsu looks back and forth between them, unable to stop from reaching out. “may i?” 

another silent exchange, but this time, she can see his ears, twisting in opposite directions, questioning.

“up to you,” shouyou murmurs gently to his boyfriend, but then natsu’s hand is brushed by something soft and a little bit coarse. that must be a yes, then. she strokes the fox tail, looking up into atsumu’s face. he’s got his eyes squeezed closed like he’s trying to hold himself together, so she digs her fingers just a little deeper, ruffling his fur as she goes, and watches his lips part. 

shouyou’s still right there, pressed reassuringly into atsumu’s side, but natsu can’t help herself—she scritches her nails all the way into his thick fur—the way she’s always done to make dogs kick their paws—and yanks, just light enough that shouyou won’t notice. the tiny groan that comes out of atsumu’s mouth makes her heart skip, but not as much as a split-second later, when his eyes flash open and meet hers, embarrassed and accusatory.

she quirks an eyebrow, so quick he might not even realize he’s seen it. “it’s so soft,” she says sweetly. 

natsu keeps his eye contact as she does the same thing again, watching him flush as he struggles not to react to the sensation. “thank you for trusting me.”

when she reaches up high, he tips his head down obligingly, holding his breath and allowing her to touch the silky warmth of his ears. and once she can see over his stooped form, she sees osamu standing in the doorway with a frown. he glares at her and walks away, tail curling against the door frame.

-

the next day, the black jackals have shouyou and atsumu booked for a long practice on top of extra hours of “PR bullshit,” as atsumu calls it. osamu is on her as soon as their brothers leave the house. she’s been waiting for it.

“what d’ya think it is yer playing at, huh? like i didn’t see you fuckin’ _fondling_ ‘tsumu last night, right in front of your own brother?” 

he’s standing close, towering over her, but she bats her eyelashes up at him with a grin. “why, ‘samu-san? are you jealous? you want me to play with your tail, too?” she reaches out toward it but it twitches away. “or are you just the one in charge of who gets to touch _his_?”

“i don’t think i’m the one who’s jealous,” he growls, walking her backward until she hits the counter and caging her in with his arms. his tail sweeps across her bare legs, making her shiver. “i’ve already got everything i want. but _you_ …i think ya might be just a little jealous. am i right?”

“what if i say yes?” she whispers, pressing a hand against his chest. 

“then i might have an idea for ya,” he says, leaning in, tipping her face up toward his. “if yer interested.”

natsu closes her eyes and waits for the kiss, but all she feels is a warm huff of laughter as he turns and walks away. 

-

“it depends on what it is ya actually want,” osamu had said later. “if it’s what i think it is… well. that’s on you. i can’t do shit about that.”

she hadn’t quite known what he meant when he said it—it was easy to be jealous of shouyou, for winning the hearts of his twin lovers, for being worthy of witnessing whatever magic had granted them the _fox thing_ —which none of them were able to explain in the least, beyond “it’s always been like this, but we mostly don’t show ‘em off to people”—and for whatever it was that happened almost every night to make him make those noises while she squeezed her legs together until her muscles burned.

osamu told her what to do, so she was going to do it. she trusted him to handle it, trusted she wouldn’t have to explain herself, because how could she possibly explain herself? 

so the next night, only a few days before she’s scheduled to leave, natsu doesn’t bother pretending to be asleep. and osamu doesn’t bother pretending to sneak. he comes to her, first, on his way to the bedroom, and offers her his hand. “ready, nacchan?”

she feels almost shy, suddenly, and like she’s not wearing enough, which is ironic, considering what they’re about to do. she peels back the covers and shivers at the cool air, feeling her nipples tighten under her thin nightshirt along with her goosebumps. osamu glances down and smirks. “cold?”

“no,” she says stubbornly, crossing her arms, and he chuckles, letting his fingers graze her waist as they walk. there’s murmuring coming from behind the door, and the reality of who’s behind it makes natsu pause, too nervous to enter first. “c’mon, kid,” osamu whispers with a wink, dropping his hand to pat her on the butt. “this is what ya want, right? you’re okay. i got ya.”

he opens to door to reveal shouyou and atsumu, bare-chested and entangled in bed, eyes bright with surprise, but not shocked. 

“don’t mind us,” osamu rumbles, sitting on the edge of the bed and pulling her into his lap.

-

it’s good. it’s better than good; it’s like a dream, to be here, heart-poundingly close… and it should be enough, she thinks, playing her fingers through osamu’s chest hair as he kisses her, gently and firmly, like he’s showing her something important. it’s exhilarating, pressed up against this older man in just her flimsy, girlish panties, hearing the sounds of her brother getting sucked off only a few feet away. 

shouyou’s breathy groans are familiar from the previous nights, sure, but she knows them better than that, too… knows them from growing up in the same house, listening to him gasp into the phone late at night with oikawa-san, hearing him figuring out what feels good all by himself and doing the same.

it should be enough, fooling around in the same room with another couple—scraping her face raw on the late night stubble of her brother’s boyfriend’s _brother_ , whom she knows for a fact shouyou’s also been sleeping with. 

but by now she’s figured out it’s not just shouyou that’s been sleeping with him. that’s the part that she can’t stop thinking about, can’t stop wondering about. can’t get out of her head. it makes her feel hot and flushed and guilty, even as she’s squirming in osamu’s lap as he wraps his big hands around her tiny waist and grinds her down against him. 

he moves like he expects her to be bigger. expects her to be heavier. like shouyou, sure, but also…

she opens her eyes, but osamu’s not looking at her. she doesn’t even have to look to know where he’s looking and she feels a stab of jealousy, but she’s not even quite sure in what direction.

does she want to have atsumu, too? the way she was able to pull those sounds out of him, that pouty betrayal, just by pulling on his tail… but shouyou was right there, then, too. like she was playing with his toy right in front of him. 

natsu winds her hands into osamu’s hair, feeling for his fox ears and when she finds them, so soft on her fingertips, all she wants is to bite them. she squeezes osamu between her thighs and his hands drop from her waist to grip her hips, guiding her as she moves on top of him, as wet and aimless as her mouth on his. 

“i,” she pants into his mouth, “i, they—” 

“hm?” he hums against her as one of his hands tests the elastic boundary of her underwear. she spreads her legs to let him in, even as she mumbles her brother’s name.

it’s too quiet for shouyou to hear her, but atsumu seems to. he watches her writhe in the palm of osamu’s hand as he swallows shouyou’s cock and lets his mouth get fucked. then he reaches out to beckon them closer.

osamu stands up and walks them closer toward the others, holding her to him one handed as she clings, legs around his waist, until he lowers her down again. when he spreads her gently out onto the bed, atsumu pulls back, pressing shouyou flat beside her. she’s close enough that she can feel his heat on her bare skin and it scares her, so she rolls toward osamu, who gathers her up in his arms but crowds close nevertheless, fox tail caressing her legs until she squirms away and presses back to back against her brother. 

atsumu reaches across shouyou to place a wide, warm hand on her hip when osamu drags her knee out and up, wrapping her leg around him, but it’s not until osamu grinds the heel of his hand against her clit and makes her keen that shouyou finally says anything.

“na—nacchan?” his voice is shaky when he does. “do...do you want me to roll over?”

osamu’s hand still has her so breathless that all she can do is nod. she feels it when he does, feels how hard he still is, hot and close against her ass as the twins sandwich them together. 

“is this okay?” shouyou mumbles into the back of her neck, fighting to hold his hips still despite atsumu starting to stretch him open with lube-slick fingers. fighting not to rut against her for friction and to escape atsumu’s insistent thrusts.

“yes,” she whispers into osamu’s throat. she drags her own fingers down osamu’s chest until she can wrap a hand most of the way around his cock, making him swear. she rubs him against her soaked panties, and then moves them aside until she can feel the velvet heat of him against her slit. he slides against her as she reaches behind herself to grip shouyou.

the wounded, desperate sound shouyou makes is unlike anything she’s ever heard before, but all he can do is suck in his breath when she nestles his dick in between her cheeks, holding him there and feeling his pulse as he humps against her in time with both twins’ fingers. 

then atsumu murmurs something into shouyou’s hair, and the next thing natsu knows, he’s clinging to her, biting down on her shoulder as atsumu shoves his way inside, crushing her against osamu’s chest until she uses her legs to pull his hips into hers, too, splitting herself open on the thickness of his cock. 

for a frantic, overwhelming moment, all she sees is white, the delicious pressure of being pinned between them, inside and out, almost unbearable. she only realizes she’s whimpering when a hand—atsumu’s?—meets her lips, giving her something to suck, something to bite. 

the feeling keeps building, centered around the gravity well in the center, where shouyou has his arms wrapped around her, clutching and squeezing at her small breasts, rubbing himself desperately against her ass, cock only centimeters from where osamu’s fucking her deep and sure just like atsumu’s doing for him. and when natsu finds the angle—that magic angle where osamu’s sliding across her clit on every single stroke, and her brother’s got her nipples pinched so hard she could scream, but she can’t, because atsumu’s still fingerfucking her face—she comes so hard she cries.

-

the next time natsu opens her eyes, she’s curled up in shouyou’s lap. he’s pressing soft kisses to her cheeks and her forehead and her hair, and she pretends to be asleep for a moment longer to enjoy it—and to enjoy the beautiful nearby sight of osamu, who’s moved onto fucking his twin into the mattress as atsumu whines and writhes beneath him, his soft tail fisted harshly in osamu’s hand.

“hey,” she whispers shyly, pulling back to look shouyou in the face. 

“hey,” he whispers back, with a lopsided grin, chewing on his lower lip. “are we…” he starts, but fizzles out, unsure what to say. 

“yeah,” she says back, smiling, and kisses him on the mouth. 

“...like them?”

“yeah,” she says again. “i think so.”

“oh,” shouyou says, his eyes wide. “then, maybe all of us…”

natsu cuts him off with another kiss, and this time he returns it, and then some, turning her easily around in his lap and parting her lips with his tongue as atsumu cries out, muffled against the bed, as he comes into osamu’s hand. 

then osamu groans, deep, too, and reluctantly pulls out, and the hinatas pause in their making out to watch as his cum drips slowly back out of atsumu.

“maybe all of us,” natsu echoes quietly, full of wonder. osamu meets her eyes and winks.


End file.
